Mechaniscally-driven type-rod typewriter



1,638,602 T. STIEBEL MECHANICALLY DRIVEN TYPE ROD TYPEWRITER 7 Aug. 9 1927.

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UNITED STATES 1,638,602 PATE'T orrics.

'rnnonoa STIEBEL, or BERLIN, GERMANY.

MECHANICALLY-DRIVEN EFYIIEE-R01'.) TYPEWRITER.

Application filed November 19, 1926, Serial No. 149,403, and in Germany April 12, 1923.

This invention relates to mechanically. driven type-rod typewriters.

In connection with type-rod typewriters it is already known to have the types pressed against the platen by a cam shaft. In the arrangement known the motion of the cam shaft is released by the advance of the type.

This brings about the inconvenience of a continuous change between stops and jerks lever typewriters but not yet with type-rod typewriters.

Mechanically driven type-rod typewriters are however an essential advance as compared with type-lever typewriters since they combine the noiseless impression of the types inherent in type-rod typewriters with aneasy operation of the key-levers which in a double sense a'fi'ords less strain on the operator and increases the writing capacity of the same.

A considerable simplification of the drive is arrived at according to the invention by the driving element, viz, the cam shaft being at the same time the element returning the key-levers into their original position so that special return-springs etc. are dispensed with. In view of the particular function of the typewriter some measures are necessary in order to compensate for the eventual difference of time between the depression of the key and the release of the key-lever accomplished by the cam shaft for the lift of the latter. According to the invention this intention is fulfilled in that the tension of spring clips, holding the keylevers in their initial position is adjusted in such a way that the key cannot be released until a spring disposed in the key sleeve has undergone such a preliminary tension that after the key-lever. having been released from the spring clip its bearing against the cam shaft is fully ensured during the impression period. On account of the short impression stroke of the different type-rods lifted for printing these rods may be arranged 1n three planes behind each other sothat the design of the whole typewriter standing the invention being omitted.

Fig. 2 above.

Fig. 3 is a diagram showing the type rods radially arranged in three different planes tangential to the plates and in normal position.

Fig. 4 is a similar View of the same, showing one of the type rods in printing position.

The double armed key-lever 1 (Fig. 1) is revolvable around the fixed shaft 2 as far as position 1. At its front end it bears key 3, which is rigidly connected to sleeve 4 by a bar. On the side showing towards the key-lever 1, sleeve 4 is longitudinally slotted and may be slid over two guiding washers 6 and 7 while working against the pressure of spring 5 which is enclosed and slightly is the typewriter as seen from compressed in its starting position. The air contained in the sleeve may escape by the longitudinal slot. To theother end of keylever 1 is attached at 8 a type-rod 9 which is arranged in a Vertical position, slides in a guide 10 and has two. types 11 and 12 on rear arms of the key-levers- Shaft 15 is driven by a small electromotor 16 v(Fig. 2).

The number of revolutions per minute of this motor may be modified at will by means of a small rheostat. Cam shaft 15 is arranged to extend over the fullwidth of the type-writer and is mounted at both ends preferably in ball bearings.

In the position of cam shaft 15 shown in i Fig. 1, key-lever 1 can not change its position since it is hindered from moving by the longitudinal projection of the cam shaft. But immediately after the cam shaft has turned through a small angle the key-lever of spring 14 by the tension of spring 5 so. that the force of spring 5 then freed maysafely bring the key-lever,' which follows cam shaft 15, into its other extreme position 1. As soon as the key-lever attains thisposition, the cam of collaw 18 revolving. in

'phase with cam shaft 15 will press the typerod 9 attached at- 8 against the platen with a stroke of about 1 millimeter.

This pressing is accomplished by means of a roller 19 running on cam collar 18 and which is mounted at one end of a connecting rod 23 longitudinallyv adjustable at '20 and acting with its other end at 21 upon a push rod 22. This arrangement permits of modifying the force of pressing at will by changing the length of connecting rod 23 so that the operator is enabled to make any number of carbon copies without necessity 01 incrcasedctfort. According to the position of the platen, which as usual is vertically displaced by a shift key, either type 11 or 12 will be pressed thereagainst. Connecting rod 23 returns into its original. position under the action of a spring 24: pressing upon the washer of connecting rod 23. Meanwhile cam shaft 15 has continued to turn and it now pushes back by its longitudinal projection the key-lever into the original position 1 of the same in which said lever at its end 13, is caught and retained by spring clip 14.

All key-levers accomplish the same movement. Their shorter arms are compensated in Weight as compared with the longer ones so that the function. of the shorter key-levers exactly. corresponds to that of the longer ones. 1

The type-rods attached to the key-levers are so arranged that when being pressed against the platen they permit of the keys tilting round the lower fulcrum, but imme diately after theimpression of the type the guides 10 again take up the rod deviated "for about 1 millimeter, this efiect being acoomplished by the spring 66.

The guides 10 are so arranged that all tare.

neeaeoa type-rods are radially led towards the point of impression in planes tangential to the platen. Ll'n order to obtain shorter approaching ways for the different type-rods the lat-- ter are preferably disposed in three difierent,

planes tangential to the plate'n so that each of these planes comprises one third of the guides, the planes being radially arranged,

behind each other in a direction perpendicular to the center line of the platen. The tangential planes do not touch the platen but terminate at a short olistance'betore'the same. i

When being lifted for printing the typerods seize the guide fork 25 of the ink rib- Icon 26 (Fig. 1) and lift it too, so that the latter gets between thc platen and the types as these .are pressed, against the platen. When the type-rod is lowered the ink ribbon 26 slides down again until it touches-a stop.

l Vhat I claim as my invention, and desire to secure by Letters Patent, 'is

1. In amechanically driven type-rod typewriter, a key lever ful'crumed at a point intermediate its ends, a type. rod pivotally connected to said key lever, a push rod, a connecting rod to strike saidpush. rod and thereby impart printing stroke to the type rod and a continuously revolving shafthaving a cam to engage said key lever and to actuate said connecting rod.

2. A typewriter as claimed in claim 1, in

which said connecting rod is longitudinally adjustable.

3. A typewriter as claimed in claim 1, in which a spring is active to move the type rod back from impressing position.

1. A. typewriter as, claimed in claim 1, in which a detent is provided to releasably normally hold the key lever in normal position and a key and spring are provided for actuating the key lever, the said spring cushioning said key and when under compression countervailing the, detent.

5. A typewriter'as claimed in claim in which the type rods are pivotally jointed to the key levers and guides are provided for the type rods, said guides being radially arranged in three difi'erent planes tangential to the platen and in which guides-said type rods are slidable.

In testimonywhereof I afiix my signarnnonon STIEBEL.

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